Gender Differences in the Prevalence of and Factors Related to Non-Suicidal Self-Injury among Middle and High School Students in South Korea

This study was conducted to estimate the prevalence of non-suicidal self-injury (NSSI)-the most severe mental health problem among South Korean adolescents in 2019. The participants were students from 12 middle and seven high schools in a single city in the metropolitan area in South Korea. A cluster-random sampling method was used-one class per school year at each middle and high schools. Every student in the selected classes was investigated. The final number of selected classes and students were as follows: 36 classes, 1074 students at middle schools; 35 classes, 873 students at high school. Data were obtained using a self-administered online questionnaire. The 12-month prevalence of NSSI was 8.8% among Korean adolescents, 2.85 times higher for female than male students (13.4% vs. 4.7%). For the school grade, the multivariable-adjusted odds ratio [mOR] was 3.89 times (95% confidence interval [CI] 1.35-11.26) higher for the group with the highest school records compared with the middle group for male students, while such pattern was not observed among female students (mOR 1.11, 95% CI 0.54-2.26). The risks for NSSI were higher among female students with lower economic status, compared with those with higher economic status (mOR 4.16, 95% CI 1.43-12.05). In contrast, economic status did not indicate higher risk among male students (mOR 1.43, 95% CI 0.42-4.84). This study suggests that the risk for NSSI among adolescent students may be different according to gender and comprehensive interventions from schools against NSSI may need a gender-sensitive approach in South Korea.